Agricultural equipment, such as a tractor or a self-propelled combine-harvester, includes a prime mover which generates power to perform work. In the case of a tractor, the prime mover is gas powered engine or a diesel engine that generates power from a supply of fuel. The engine drives a transmission which moves wheels or treads to propel the tractor across a field. In addition to providing power to wheels through a transmission, tractors often include a power takeoff (PTO) which includes a shaft coupled to the transmission and which is driven by the engine.
In both gas powered and diesel powered engines, the amount of work performed not only includes moving the vehicle along a road or field, but delivering power to a wide variety of accessories driven the engine and often by the PTO. The PTO of agricultural equipment drives what is known as farm implements or attachments including discs, spreaders, combines, or bailers. Some work vehicles include a hydraulic machine having a hydraulic pump which can be used, for instance, to raise or lower a piece of equipment such as a mower. In other embodiments, the PTO can be coupled to a number of different types of equipment, including but not limited to log splitters, pumps, concrete mixers, mulchers, chippers, balers, harvesters, spreaders, and sprayers.
Other work vehicles having prime movers include construction vehicles, forestry vehicles, lawn maintenance vehicles, as well as on-road vehicles such as those used to plow snow, spread salt, or vehicles with towing capability. While each of the work vehicles, including the agricultural equipment described above, often include gas powered combustion engines as the prime mover, many of the work vehicles use diesel engines, due in part to the higher torque available from a diesel engine.
Current engines include a large number of complex air control systems directed to controlling airflow into and out of the engine to provide increased fuel efficiency, as well as to reduce the amount of pollutants generated by the engine. Because power from the engine must be provided not only for moving the vehicle, but for powering other equipment or accessories as well, the design of engine systems, engine components and engine subsystems take into account the control the operating temperature of the engine systems and the related components. Consequently, the increased demands for a work vehicle to deliver power require that the temperatures of the engine and subsystems should be adequately compensated for and/or controlled.
Significant challenges exist in an engine system where brackets are located adjacent to or between heat-sensitive components in the high temperature air systems. Not only is temperature control important, consideration of the engine system resonant frequencies with respect to engine firing frequencies should also be considered. Another consideration is to provide a system having a sufficiently rigid or stiff design which achieves engine and engine system resonant frequency goals, while still allowing sufficient compliance to enable relative thermal displacements between components. Otherwise, high thermal strains are produced, which can lead to thermal fatigue failures. Prior designs have faced significant challenges in this area, but have only provided limited solutions. Consequently, what is needed therefore is an engine system which reduces thermal strains and mitigates thermal fatigue risks.